I guess I will join Eric in his puzzlement. "Education" and "increased use of birth control" just don't seem plausible because the years in which teen pregnancy have been falling are marked by widespread use of abstinence-only "education" methods which tend to contain many inaccuracies and which discourage the use of condoms and contraceptives (because if you take the pill, get an IUD or simply have a supply of condoms with you, that implies that you're planning to have sex). And access to contraceptives has been getting more difficult because more and more family planning centers are under attack and have had to close or reduce hours or increase costs. So I'll admit I'm baffled.

Perhaps parents have taken up the burden of comprehensive sex ed in the wake of schools falling down on the job? Not terribly likely from conservative, evangelical families. Perhaps doctors are having more chats with their young patients? Perhaps schools are slipping in comprehensive sex ed despite their abstinence-only funding? Or perhaps - and geez I hate to even think this - abstinence-only is somehow working? Please someone, tell me what I'm missing.

@Dienne: I don't know whether or not today's teens are better educated about sex and pregnancy than their parents and grandparents were, but I wouldn't doubt it. Education doesn't only come from teachers and parents, after all. Teens talk among themselves, and the Internet is a terrific source of information that wasn't available to previous generations.

Culturally, I think there is more of a sense that teen pregnancy is a bad thing. In 1960, a teen who got pregnant (or who got somebody else pregnant) would have to find a job, get married, and enter the adult world, but that world was probably only a few years off anyway. What's the big deal having a kid at 16 or 18 if you knew you were probably going to have a kid by the time you were 20, 21 tops? Today, a lot of people won't even consider having kids until they're out of college and have a few years of work experience under their belt...we're talking 25 at the earliest. That's not universal, of course, because college is not universal (and neither are jobs) but it does seem to be a pretty popular mindset. (Actually, I'd be curious to see how the trends in teen birthrates correlate to the trends in birthrates for other age groups.)

Birth rates will start climbing once Republicans shut down abortion clinics in their states (example: Mississippi) and continue de-funding Planned Parenthood (example: Texas). Then watch the Republicans whine when they get hit with the bills for all of those unplanned and unwanted births.

The more interesting line is the under-18 one, because the 18-19 one is not just what we typically think of when someone says "teen pregnancy"; it also includes a fair number of married women (especially in the earlier years of the chart).

The label "teen pregnancy" has also bothered me, when it's used to mean pregancies by anyone with a "teen" as part of their age. Eighteen and nineteen-year-olds are adults, after all. What we're really concerned with is pregnancies by high-schoolers/minors, right? Or is it a public health-type concern when a 19 year old gets pregnant?

At any rate, I've long thought that "teen" birth rates mirror those of their older sisters, and would be interested to see if this is the case. It's true that there are potential impacts of long-lasting contraception, and questions of acceptability of abortion (because these are birth rates, so they don't measure the frequency of pregnancies per se). But I think that motivation is the larger factor, and teens pick up general cultural attitudes in support of or against (unmarried) pregnancy.

back in the 50's and 60's, is what not uncommon for a girl to graduate high school in May and be married in June when she is 18. So having a baby when she is 19 was not uncommon. Does this include only unwed teen mothers or all teen mothers?

Another possible reason is now the teenagers are being raised by mothers who were on the pill when they were teenagers, so more mothers are probably initiating the birth control conversation.

Women have more career options now, so being a mother isn't the only option in life. (There have been related articles about our country not producing enough offspring to provide for the next elderly generation).

Another thing: all three age groups have followed the same general trend since around 1975, but between 1960 and 1975, there was a precipitous and unique drop in births among 18-19 year olds. I assume that easier access to contraception for adults was behind that drop, but there may have been other factors as well.

About "Change of Subject."

"Change of Subject" by Chicago Tribune op-ed columnist Eric Zorn contains observations, reports, tips, referrals and tirades, though not necessarily in that order. Links will tend to expire, so seize the day. For an archive of Zorn's latest Tribune columns click here. An explanation of the title of this blog is here. If you have other questions, suggestions or comments, send e-mail to ericzorn at gmail.com.
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Contributing editor Jessica Reynolds is a 2012 graduate of Loyola University Chicago and is the coordinator of the Tribune's editorial board. She can be reached at jreynolds at tribune.com.